I am not sure either what they are in the hickory trees. I must have been told but I probably forgot. The one I cut for fire wood did not have them but 30 feet away another bigger older tree does. That is going to fire wood also as part of my thinning plan. The warts, burrels or what ever does not sem to hurt the wood if you want to take a log out for sawing. I have in the past made outdoor furtinure from hickory . It is one tough wood.
Maple syrup makers never die, they just evaporate.
Kubota M-5040,Kubota B-2650,Kubota XRT 900, Sugarhouse is now a guest cottage.